JPH0843460A - High-harmonic measurement analysis system - Google Patents

Abstract

PURPOSE:To clearly and quickly recognize the occurrence location and state of high harmonics by analyzing high harmonics up to a specific degree from current waveform data and displaying the waveform of high harmonics in time series. CONSTITUTION:Analyzers 11 and 12 receive detection signals from current sensors A1-A5 and voltage sensors V1-V3, continuously record them at a lapse of time, and performs a fast Fourier Transformation of the recorded current and voltage waveform data for analysis. Then, waveform display data for displaying the waveform of each high harmonic up to for example 49th order are generated from the fundamental waves of received current, received voltage and load current, and load voltage. The waveform display data are transmitted to a personal computer 15 via cables 13 and 14 and are stored in a hard disk. By running a high-harmonic analysis software stored in a floppy disk 16 for the waveform display data, the high-harmonic waveform from the fundamental wave to the 49th at a detection part can be displayed successively in time series.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a harmonic measurement / analysis system by continuous multipoint simultaneous measurement for continuously measuring and analyzing the generation state of harmonics in electric power consumers.

[0002]

BACKGROUND OF THE INVENTION and Prior Art In recent years, the development of power electronics used in power converters, general-purpose inverters, household electric appliances, etc. has been remarkable, and is becoming more and more popular due to its high performance and high efficiency. However, along with this, harmonic components generated during the switching operation of the central element of power electronics flow out to the distribution system, increasing the distortion of voltage and current, and damaging various equipment, or Unnecessary actions are often given.

In particular, the reactor connected in series with the high voltage phase-advancing capacitor tends to be damaged a lot. Therefore, there is a problem that a large amount of cost is required for replacing or repairing a damaged electric power device, and the suspension period is relatively long, resulting in a large economic loss. Therefore, conventionally, in order to confirm the generation state of harmonics, for example, the harmonic measuring means for measuring the instantaneous value of the voltage or current only at the power receiving point and then analyzing the harmonics with the power analyzer, or the load circuit of the measurement target A harmonic measurement / analysis means for measuring instantaneous values of voltage and current and analyzing harmonics with a power analyzer is adopted.

[0004]

However, according to the above-mentioned conventional harmonic measurement / analysis means, there are the following problems. (1) It is not possible to specify the trend of the harmonics throughout the day and the maximum value. (2) Generally, the operating hours of each load in the power consumer are random, so it is difficult to determine when and from what load the harmonics are generated. (3) When attempting to measure a plurality of points at the same time, a large number of manpower is required, and the measurer is restrained for a long time during that time, and sometimes the person stays up all night. (4) Since it is a means for recording the measurement data on the recording paper,
When measuring for a long time, the recording paper becomes long and inconvenient to store, and when processing data, it takes time to retrieve the data, and the input work to input to the computer is troublesome. However, the time-series processing takes time and it is troublesome to see the graph.

Therefore, in the present invention, currents are simultaneously and continuously detected at a plurality of measurement points, and the current waveform data at each measurement point is automatically recorded based on each detected current, and then each current waveform data is recorded. -By analyzing the harmonics up to the predetermined order and displaying the waveform of the harmonics in time series,
It is an object to solve the above conventional problems.

[0006]

The technical means for solving the above-mentioned problems is to use a harmonic measurement / analysis system in which a power receiving current in a power receiving circuit to which a phase advancing capacitor is connected and a voltage from the power receiving circuit are on the primary side. A plurality of current detecting means for detecting the primary side current of the transformer and the load current in the load side circuit and outputting each detected current signal, and the detected current signal output from each of the current detecting means. Is continuously recorded as current waveform data with time, and the current waveform data recorded in the waveform data recording means is analyzed to analyze the received current and the transformer. Waveform display data for displaying the waveforms of the primary current and the harmonics of the load current from the fundamental wave to the predetermined order in time series.
Waveform display data calculating means for calculating data, and the fundamental waves of the received current and the primary side current of the transformer based on the waveform display data calculated by the waveform display data calculating means. Waveforms of the harmonics from the fundamental wave to the predetermined order of the current flowing through the phase-advancing capacitor by subtracting the sum of the primary side current of the transformer from the received current for each of the harmonics up to the predetermined order. Based on each of the waveform display data calculated by the waveform display data calculating means and the advanced capacitor current waveform display data calculating means. And a waveform display means for displaying the waveforms of the harmonics of the received current, the primary side current of the transformer, the load current, and the phase-advancing capacitor current from the fundamental wave to the predetermined order.

Further, the received current and the received voltage in the power receiving circuit to which the phase advancing capacitor is connected, and the load current and the load voltage in the load side circuit of the transformer to which the voltage of the power receiving circuit is applied to the primary side are detected, The waveform display means displays the direction of the power of each harmonic so that the inflow and outflow of each harmonic can be determined.

[0008]

According to the harmonic measurement analysis system having the above configuration,
When each current detecting means detects the received current in the power receiving circuit, the primary side current of the transformer, and the plurality of load currents in the load side circuit and outputs each detected current signal, the waveform data recording means detects the current. The detected current signals output from the respective means are continuously recorded as current waveform data. Then, the waveform display data calculating means analyzes the current waveform data recorded in the waveform data recording means to calculate the basic wave of the received current, the primary side current of the transformer, and the load current. Waveform display data for displaying each harmonic waveform up to a predetermined order in time series is calculated. Further, the phase-advancing capacitor current waveform display data calculating means calculates the fundamental wave of the received current and the primary side current of the transformer based on the waveform display data calculated by the waveform display data calculating means. To the specified order of harmonics, subtract the sum of the primary side current of the transformer from the received current to obtain the waveform display data of the harmonics of the current up to the specified order of the current flowing through the phase-advancing capacitor. Calculate The waveform display means receives power, the primary side current of the transformer, and the load based on the waveform display data calculated by the waveform display data calculating means and the phase-advancing capacitor current waveform display data calculating means. The current and each waveform of each harmonic from the fundamental wave of the phase-advancing capacitor current to the predetermined order are displayed in time series.

Further, the received current and the received voltage in the receiving circuit connected to the phase advancing capacitor, and the load current and the load voltage in the load side circuit of the transformer to which the voltage of the receiving circuit is applied to the primary side are detected, It is possible to display the direction of the power of each harmonic by the waveform display means and determine the inflow and outflow of each harmonic.

[0010]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a power distribution single line system diagram of an electric power consumer, and shows a plurality of detection points for detecting current and voltage for measuring and analyzing harmonics in the power distribution system. In order to detect the received current in the three-phase three-wire power receiving circuit 1, for example, two current transformers CT1 and CT2 arranged on the R-phase and T-phase electric wires are respectively provided with current sensors A1,
A2 is connected to the three-phase meter transformer PT1, and voltage sensors V1 and V2 for detecting the received voltage between the SR phases and the ST phases are connected to the transformer PT1.

Further, in order to detect the primary side currents of the transformers 2 and 3, current sensors A3 and A5 are connected to the current transformers CT3 and CT5, respectively. Furthermore, in order to detect the secondary side current of the transformer 2, a current sensor A4 is connected to the current transformer CT4. Further, a voltage sensor V3 is connected to detect the secondary side voltage of the transformer 2.

On the other hand, the phase-advancing capacitor 4 has a reactor 5
Are connected in series, and the voltage of the power receiving circuit 1 is applied to the series reactor 5. In order to detect the current flowing in the phase advancing capacitor circuit, it is necessary to connect the current sensor A6 to the current transformer CT6 as shown by the broken line, but in general, the current transformer CT6 is provided in the phase advancing capacitor circuit. Since it is not provided, it is difficult to directly detect the capacitor current with the current sensor A6. Therefore, in this embodiment, the “current method” is used, which indirectly calculates the current flowing through the phase advancing capacitor circuit. According to the "current method", in the case of the power receiving and distributing system as shown in FIG. 1, the magnitude of the current flowing in the phase advancing capacitor circuit is determined from the current detected by the current sensor A1 to the current detected by the current sensor A3 and the current detected by the current sensor A5. Since it has been proved that it is almost equal to the value obtained by subtracting the sum of and, by performing this calculation for each of the harmonics from the fundamental wave to the 49th order, for example, the 49th order from the fundamental wave of the current flowing in the phase advance capacitor circuit. The current value of each harmonic up to is calculated.

FIG. 2 shows the current flowing through the phase advancing capacitor circuit in the actual measurement method in order to verify the certainty of the "current method".
3 is a graph showing three types of the "current method" and the voltage method, that is, the method of obtaining the received voltage by dividing the received voltage by the impedance of the phase advancing capacitor circuit. As shown in FIG. 2, since it is clear that the “current method” accurately reproduces the measured value, the fundamental wave of the current flowing in the phase advance capacitor circuit is used in the present embodiment by using the “current method”. The current value of each of the harmonics up to the 49th was calculated.

FIG. 3 is a block diagram showing a comparison between the conventional system of the harmonic measurement analysis system and the system of the present invention.
In FIG. 3, V1 to V3 common to the conventional method and the method of the present invention
Is the voltage sensor shown in FIG. 1, and A1 to A5 are the current sensors shown in FIG. Further, "3195" is a digital power analyzer 11, and "883"
2 "is also an analyzer 12 having a similar function.

The harmonic measurement analysis system of the present invention is
A personal computer (PC98) 15 is provided which is connected to the two analyzers 11 and 12 by RS-232C reverse scales 13 and 14. The personal computer 15 is configured to run its program when the harmonic measurement analysis software stored in the floppy disk 16 or the like is set. Further, a cable 17 for transmitting a synchronization signal is connected between the two analyzers 11 and 12 so that signals from the current sensor and the voltage sensor are synchronously fetched.

The current sensor and the voltage sensor are connected to the analyzers 11 and 12 as described above, and the analyzer 1
RS-23 with 1, 12 and personal computer 15
The 2C reversal cables 13 and 14 electrically connect to each other, and the cable 17 for transmitting the synchronizing signal further connects the analyzer 11 and
The measurement and analysis of harmonics is started with 12 connected.

When entering the harmonic measurement analysis, the personal computer 15 automatically sets the various conditions necessary for the measurement, such as the measurement date, the measurement start time, the measurement end time, and the sampling time. Current detection signals and voltage detection signals are input to the analyzers 11 and 12 in real time from the sensors A1 to A5 and the voltage sensors V1 to V3.

The analyzers 11 and 12 input the current detection signal and the voltage detection signal as current and voltage waveform data, continuously record them with time, and record the recorded current and voltage waveform data. A high-speed Fourier transform is performed and analyzed to generate waveform display data for displaying the waveforms of the received current, the received voltage and the load current, and the harmonics up to, for example, the 49th harmonic of the load voltage.

The waveform display data is transmitted to the personal computer 15 via the RS-232C reversible cables 13 and 14 and stored in the hard disk. This waveform display data is obtained by running the harmonic measurement analysis software stored in the floppy disk 16,
49 from the fundamental wave at the current and voltage detection points shown in FIG.
The harmonic waveforms up to the next are displayed in sequence on the personal computer.
It can be displayed on the display unit of the computer 15 in time series.

FIG. 4 is a basic flowchart of the harmonic measurement analysis system. As shown in FIG. 4, after the measurement purpose, the measurement method, the measurement procedure, and the selection of the measuring instrument, the analyzers 11 and 12 and the personal computer 15 are used in appropriate places. To do. The current sensors A1 to A5 and the voltage sensors V1 to V3 are connected to the analyzers 11 and 12, and the analyzers 11,
12 and personal computer 15 RS-232C
Electrically connected by reversal cables 13 and 14,
A cable 17 for transmitting a synchronization signal connects between the analyzers 11 and 12.

Next, a menu screen is displayed on the display section of the personal computer 15. Then, a setting file is created for setting the voltage and current ranges, etc. according to each menu operation, and then data is exchanged between the personal computer 15 and the analyzers 11 and 12 to execute the hardware. Make settings.

Next, the connection check between the current sensors A1 to A5 and the voltage sensors V1 to V3 and the analyzers 11 and 12 is checked, and if there is no error, the personal computer 15 is used to measure the measurement date and time. Set various conditions required for measurement such as start time, measurement end time, and sampling time.

When the various conditions necessary for the measurement are set as described above, the standby state is set, and at the measurement start time, the current sensors A1 to A5 and the voltage sensors V1 to V3.
From this, the current detection signal and the voltage detection signal are fetched into the analyzers 11 and 12. And the analyzers 11 and 12
Current detection signal and voltage detection signal
When it is input as a data, it is continuously recorded with time, and the recorded current and voltage waveform data are subjected to high-speed Fourier transform for analysis, and the received current, voltage and load current, and the fundamental wave of voltage are used to calculate 49 Waveform display data for displaying the waveform of each harmonic up to the next is generated. This waveform display data is sequentially transmitted to the personal computer 15 until the measurement end time and stored in a hard disk (not shown).

Further, the personal computer 15 uses the above-mentioned "current method" based on the above waveform display data to determine the harmonics from the fundamental wave of the current flowing through the circuit of the phase advance capacitor 4 to the predetermined order. Waveform display data is calculated and stored in the hard disk.

When the measurement end time is changed, the measurement end date and time after the change is input, and the measurement is continued after it is determined that the hard disk (HD) has a sufficient capacity.

After the measurement end time, a hard disk (HD)
Call up the waveform display data for each harmonic from the fundamental wave to the 49th order stored in the personal computer 15
When it is displayed on the display section of, the file is converted so that it can be called in a short time. By this file conversion process, data for one week can be displayed in about 1 second. In this state, measurement is terminated, each sensor is disconnected, and the measuring device is removed.

FIGS. 5 to 9 show the results measured by the above-described harmonic measurement / analysis system by the personal computer 15.
5 is a waveform diagram displayed on the display unit of FIG. FIG. 5 shows changes over time in the voltage distortion rate at the power receiving point for three days. As shown in this waveform diagram, by obtaining the waveform display data in time series, the tendency of the harmonics for one day, the maximum value, etc. can be recognized at a glance.

FIG. 6 is a current waveform diagram of the R-phase, T-phase and phase-advancing capacitor circuits, and the current waveform at any time during the measurement period can be reproduced.

FIG. 7 is a waveform diagram showing the time change of the fifth harmonic current at each of the power receiving point, the power load, and the general load. It is possible to recognize at a glance whether or not harmonics are generated. The measurement points of the above-mentioned power load and general load do not match the measurement points of FIG.

FIG. 8 is a graph showing the current spectrum of the power load from the fundamental wave to the 49th harmonic. From this graph, the amount of the contained harmonic component for each order can be easily recognized. To be done.

FIG. 9 is a waveform diagram showing the time variation of the harmonic power at the power receiving point. By measuring the voltage and current at each of two points at the power receiving point, the direction of the harmonic is displayed as positive or negative power. It was done. This waveform diagram shows that the harmonic component flows in when the power value is positive, while the harmonic component flows out when the power value is negative. In this example, the fifth harmonic component flows out in the daytime. I can recognize that In addition, (* 100
0) is the effective value of the 3rd, 5th and 7th harmonics of 1000
It is shown that it is doubled and displayed.

As described above, by detecting the current and voltage in synchronization from a large number of current and voltage measurement points,
Since harmonics at each measurement point can be continuously measured and displayed in a time series instantly, it is possible to reliably recognize the location of harmonics due to load fluctuations, the time of occurrence, etc. This makes it easier to plan countermeasures for suppressing the generation of harmonics.

[0033]

As described above, according to the present invention, the current is detected simultaneously and continuously at a plurality of measurement points, and the current waveform at each measurement point is automatically generated based on each detected current. Since it is possible to analyze harmonics up to a predetermined order from each current waveform and display them in time series, there are the following effects. (1) It is possible to specify the trend of the harmonics throughout the day and the maximum value. (2) It is possible to determine at what time and from what load the harmonic is generated. (3) Even if a plurality of points are measured at the same time, since the measurement is automated, the measurer is not restrained for a long time and is not allowed to stay up all night. (4) When the waveform display data of each harmonic is called and displayed on the display unit of a personal computer or the like after the measurement end time, for example, the data for one week is displayed in about one second. Therefore, the calling of data is easy, and the generation status of each harmonic can be clearly recognized in a short time. (5) It becomes easy to take measures to suppress the generation of harmonics.

[Brief description of drawings]

FIG. 1 is a power reception / distribution single line system diagram showing harmonic measurement points.

FIG. 2 is a current waveform diagram showing the superiority of the current method.

FIG. 3 is a comparison block diagram of a conventional method and a method of the present invention of a harmonic measurement analysis system.

FIG. 4 is a basic flowchart of a harmonic measurement analysis system.

FIG. 5 is a waveform diagram showing a time change of a voltage distortion rate at a power receiving point for three days.

FIG. 6 is a current waveform diagram of R-phase, T-phase, and phase-advancing capacitor circuits.

FIG. 7 is a waveform diagram showing the time change of the fifth harmonic current.

FIG. 8 is a harmonic current spectrum diagram.

FIG. 9 is a waveform diagram showing the time change of the harmonic power at the power receiving point.

[Explanation of symbols]

 1 3-phase 3-wire type power receiving circuit 2 Transformer 3 Transformer 4 Phase-advancing capacitor 5 Series reactor 11 Analyzer 12 Analyzer 13 RS-232C reversible cable 14 RS-232C reversible cable 15 Personal computer 16 floppy disk 17 cable for synchronous signal transmission A1 current sensor A2 current sensor A3 current sensor A4 current sensor A5 current sensor V1 voltage sensor V2 voltage sensor V3 voltage sensor

Claims (2)

[Claims] 1. A power receiving current in a power receiving circuit to which a phase advancing capacitor is connected, a primary side current of a transformer to which a voltage from the power receiving circuit is applied to a primary side, and a load current in a load side circuit of the transformer. And a plurality of current detecting means for detecting each of the detected current signals, and waveform data recording for continuously recording the detected current signals output from the respective current detecting means as current waveform data with time. Means and the current waveform data recorded in the waveform data recording means to analyze the received current, the primary side current of the transformer and the harmonics of the load current from the fundamental wave to the predetermined order. Based on the waveform display data calculating means for calculating the waveform display data for displaying the waveforms of the above waveforms and the waveform display data calculated by the waveform display data calculating means. 1 of the received current and the transformer For each harmonic from the fundamental wave of the secondary current to the predetermined order, the sum of the primary current of the transformer is subtracted from the received current to obtain each harmonic of the fundamental wave to the predetermined order of the current flowing through the phase-advancing capacitor. Leading capacitor current waveform display data computing means for computing the waveform display data and each waveform display data computed by the waveform display data computing means and the leading capacitor current waveform display data computing means. −
Waveform display means for displaying the waveforms of the received current, the primary side current of the transformer, the load current, and the harmonics from the fundamental wave to the predetermined order of the phase-advancing capacitor current based on the Characteristic harmonic measurement analysis system. 2. A power receiving current and voltage in a power receiving circuit to which a phase advancing capacitor is connected, and a load current and a load voltage in a load side circuit of a transformer to which the voltage of the power receiving circuit is applied to the primary side, 2. The harmonic measurement analysis system according to claim 1, wherein the direction of electric power of each harmonic is displayed on the waveform display means so that the inflow and outflow of each harmonic can be determined.